An expanding class of mega-philanthropic institutions, most often based in the Global North but increasingly based in the Global South, has emerged as a driving force in global health. Among them, the Carlos Slim Foundation—located in Mexico City and funded by Mexican-born telecommunications tycoon Carlos Slim Helú—has spearheaded an ongoing strategy to boost chronic disease prevention in Mexico, principally through the development and promotion of a series of cutting-edge diagnostic tests. In this research article I trace the Foundation’s efforts to develop these technologies and integrate them into Mexican health policy. With these technologies serving as powerful conduits of the Foundation’s epistemic power, I show that Carlos Slim’s philanthropic investments are reshaping goals in the public health field and fostering new understanding of chronic disease risk among health officials and experts in Mexico and beyond.